THE number of mobile-phone subscribers in the 30 countries of the OECD reached nearly 933m in 2005, equivalent to around 80 for every 100 people. Tiny Luxembourg has the highest penetration rate, with 157.3 subscribers for every 100 people. Indeed, it is one of 14 countries in which there are more subscribers than people. This is partly because users increasingly have several SIM cards for use with the same phone. The rapid growth in pre-pay accounts—from 4% of total subscriptions in 1997 to 42% in 2005—is also a factor, as such accounts often lie inactive. South Korea and Japan are the only countries with more third-generation (3G) phone subscribers than 2G ones.

Source: http://www.economist.com/daily/chartgallery/displaystory.cfm?story_id=9537136